The present invention relates to syndiotactic monovinylidene aromatic polymer compositions.
Blends of syndiotactic monovinylidene aromatic and olefin polymers are known in the art, combining the toughness and solvent resistance of an olefinic polymer with the high modulus and thermoformability of syndiotactic monovinylidene aromatic polymers. U.S. Pat. No. 5,460,818 issued to Park et al. discloses a composition comprising syndiotactic polystyrene (SPS), an aliphatic alpha-olefin homopolymer, a ethylene-styrene interpolymer compatibilizer and optional impact modifiers. However, this composition utilizes nonelastomeric polyolefins, therefore high elongation and toughness, i.e. ductility, are not achieved unless the polyolefin content is high.
U.S. Pat. No. 5,395,890 issued to Nakano et al. discloses a composition containing SPS, a polyolefin thermoplastic and a rubber polymer. However, the polyolefins are again nonelastomeric.
U.S. Pat. No. 5,391,603 issued to Wessel et al. discloses a composition comprising SPS, an olefin elastomer and a nucleator. However, the olefin elastomers are block or graft copolymers which are expensive components and add significant cost to such compositions or are not thermally stable at high processing temperatures needed for SPS polymers.
U.S. Pat. No. 5,391,611 issued to Funayama et al. discloses a composition comprising SPS and a rubbery polymer such as styrene-ethylene-butadiene-styrene (SEBS). Again, a block copolymer is used, increasing the composition cost and/or decreasing thermal stability.
Therefore, there remains a need for ductility modified syndiotactic monovinylidene aromatic polymer compositions containing elastomeric ductility modifiers that are cost effective.